Disk schedulers for solid state drivers

Jaeho Kim, Yongseok Oh, Eunsam Kim, Jongmoo Choi, Donghee Lee, Sam H. Noh

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

84 Scopus citations

Abstract

In embedded systems and laptops, flash memory storage such as SSDs (Solid State Drive) have been gaining popularity due to its low energy consumption and durability. As SSDs are flash memory based devices, their performance behavior differs from those of magnetic disks. However, little attention has been paid on how to exploit SSDs from the disk scheduling algorithm view point. In this paper, we first describe behaviors of SSDs that inspires us to design a new disk scheduler for the Linux operating system. Specifically, read service time is almost constant in an SSD while write service time is not. Moreover, appropriate grouping of write requests eliminates any ordering-related restrictions and also maximizes write performance. From these observations, we propose two disk schedulers: IRBW-FIFO and IRBW-FIFO-RP. Both schedulers arrange write requests into bundles of an appropriate size while read requests are independently scheduled. Then, the IRBW-FIFO scheduler provides complete FIFO ordering to each bundle of write requests and each individual read requests while the IRBW-FIFO-RP scheduler gives higher priority to read requests than the bundles of write requests. We implement these schedulers in Linux 2.6.23, and results of executing our set of benchmark programs shows that performance improvements of up to 17% compared to existing Linux disk schedulers are achieved.

Original languageEnglish
Title of host publicationEmbedded Systems Week 2009 - Proceedings of the 7th ACM International Conference on Embedded Software, EMSOFT '09
Pages295-304
Number of pages10
DOIs
StatePublished - 2009
EventEmbedded Systems Week 2009, ESWEEK 2009 - 7th ACM International Conference on Embedded Software, EMSOFT '09 - Grenoble, France
Duration: 11 Oct 200916 Oct 2009

Publication series

NameEmbedded Systems Week 2009 - Proceedings of the 7th ACM International Conference on Embedded Software, EMSOFT '09

Conference

ConferenceEmbedded Systems Week 2009, ESWEEK 2009 - 7th ACM International Conference on Embedded Software, EMSOFT '09
Country/TerritoryFrance
CityGrenoble
Period11/10/0916/10/09

Keywords

  • Disk scheduler
  • Implementation study
  • Linux
  • Solid state drive

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